The Unit on Reproductive Endocrinology and Infertility, led by James Segars, investigates underlying causes and effectiveness of treatment for a variety of clinical reproductive disorders. This unit has the mission to conduct basic, translational, and clinical studies of importance to reproduction in the context of the multi-institutional clinical training program in Reproductive Endocrinology and Infertility. In the past year, we have continued our research on two very prevalent disorders of reproduction, uterine fibroids (also known as leiomyoma), and endometriosis. Our previous studies have revealed that genes producing the extracellular matrix (connective tissue between cells) were expressed at abnormal levels in uterine fibroids. In the past year, we have found that the extracellular matrix of uterine fibroids is abnormal is abnormally-formed, as the collagen fibers are randomly oriented and widely spaced in fibroids, compared to the compact fibers in normal uterine tissues. This finding suggests that the extracellular matrix deposited in fibroids may not be easily degraded, and might contribute to growth of the tumors. As planned, we have begun a study involving non-surgical treatment of fibroids in collaboration with investigators at the NIH Clinical Center, the National Cancer Institute and the National Institute of Environmental Health Sciences. In the ongoing collaborative study with Drs. Heiner Westphal, Chrousos, and Kino experiments have suggested a physiologic role for Brx in and related proteins in hormone action. As infertility and endometriosis affect many women attempting to have children, we continue to conduct clinical studies of endometriosis and infertility in an effort to optimize outcome of treatment for couples experiencing endometriosis or infertility.